MAKING
1 In a heavy kettle, make a roux (the flavor base for many Creole dishes) by melting butter or margarine; stir in flour. Cook, stirring constantly, over low heat, until flour turns a rich brown, about 15 minutes.
2 Stir in onion and garlic. Cook, stirring often until soft, about 10 minutes. Add tomatoes, chicken broth, water, salt, Worcestershire sauce, and pepper seasoning. Cover the kettle.
3 Simmer for 15 minutes to develop the flavors. Add crab meat and oysters with their liquor. Continue cooking, just until oysters are curled, about 5 minutes.
4 Sprinkle fill powder into gumbo and stir in to the thicken broth.